Immunochemical identification and physico-chemical characteristics of specific alpha 2 globulin of human granulocytes]

The antigen which has alpha 2-globulin mobility was identified immunochemically in leukolysate and pus extract. This antigen was localized in polymorphonuclear leukocytes by the immunofluorescence technique in the blood of healthy donors. The alpha 2-globulin of granulocytes (alpha 2GG) is not identical to lactoferrin, lysozyme, granulocyte elastase, fibronectin, fetal hemoglobin, amyloid P-component of the serum. The molecular mass of alpha 2GG is equal to 50 +/- 8 Kd. in the pus extract. The biological role of alpha 2GG is unknown.     

Synthesis and membrane protective activity of bis-sulfides derived from monoterpenoids and monosaccharides

Hydroxyl- and chloroethyl derivatives of neomenthane- and isobornanethiol in yields of to 80% were synthesized. They served as the basis for the preparation of new bis-sulfides with diacetone-protected galacto- and fructopyranose fragments in yields up to 98%. The bis-sulfides synthesized were screened for membrane protective and antioxidant properties in a model cell system (in vitro) based on their ability to inhibit the H₂O₂-induced hemolysis of erythrocytes and retard the oxyhemoglobin oxidation.     

Penetration of thyroliberin in the blood and brain regions at intranasal or intravenous administration

The maximum amounts of the thyroliberin in the blood and brain of rats at intranasal and intravenous administration were determined. It is found that rat hippocampal, cortical, and cerebellar membranes contain two types of specific binding sites (high- and low-affinity) for the labeled ligand. It was shown that, at intranasal and intravenous administration, maximum amounts of the thyroliberin were detected in the cerebellum and then in the cortex and hippocampus. The degradation of the thyroliberin in the rat brain and its regions at intranasal and intravenous administration was studied. It is shown that the degree of degradation and the formation of proteolytic products of the thyroliberin is different in different regions of the rat brain.     

Surface active properties of isobornylphenols in systems with different degrees of complexity

Interrelations between the structure of the semi-synthetic phenolic antioxidants — isobornylphenols and their surface active properties were studied in the chemical (the lecithin aggregation in hexane) and biological (the incubation with the blood erythrocytes) model systems. It has been shown that all studied compounds are able to affect the lecithin aggregation in hexane: the share of the main fraction of the L micelles decreases with increasing the share of particles of greater size. The effect substantially depends on hindered OH group and the presence of the intramolecular hydrogen bond in molecule. The cytotoxic properties of isobornylphenols (the concentration is 100 μM) are predominantly due to the molecule structure. The interrelation between the aggregate size of the main fraction of L in the presence of the studied compounds and the discocyte share during mice blood erythrocyte incubation in their presence for 4 h is revealed. Thus, this provides the possibility to assume that the ability of the different biological active substances to affect the lecithin aggregation in non-polar solvent could be used as a model system for the initial assessment of their surface active properties.     

Variation of nitric oxide content regulates the development of apoptosis in the retina

It was shown that retinal ischemia entailed apoptosis in the inner layers of the retina. Administration of an NO-synthase inhibitor suppressed the development of ischemic apoptosis. To ascertain whether nitric oxide could induce the retinal apoptosis by itself, a nontoxic NO donor—dinitrosyl iron complex (DNIC) with glutathione—was injected into the vitreous body. DNIC at low concentrations induced apoptosis in the same retinal layers as in ischemia. However, with increasing DNIC doses, the number of apoptotic nuclei decreased markedly. Simultaneous administration of excess glutathione prevented apoptosis at any DNIC dose. The obtained data demonstrate the neurotoxic properties of the excess of nitric oxide in the retina.     

FE study of bone quality effect on load-carrying ability of dental implants

Extreme stresses in surrounding bone are among the most important reasons for implant failure. Bone density (quality) is a variable that plays a decisive role in achieving predictable osseointegration and long-term survival of implants. The magnitudes of ultimate occlusal load, which generate ultimate von Mises stress at the critical point of peri-implant area for the spectrum of implants inserted into mandible with four different bone qualities (Lekholm and Zarb classification), were calculated. Geometric models of mandible segment were generated from computed tomography images and analysed with osseointegrated cylindrical implants of various dimensions. Occlusal loads were applied in their natural direction. All materials were assumed to be linearly elastic and isotropic. The investigation suggests that an implant's ultimate occlusal load indicates its load-carrying capacity. As a result, bone loss can be predicted, and viable implants can be selected by comparing the values of their ultimate occlusal load in different clinical conditions.     

A comparative analysis of the biological activity of an acid-extractable brain protein and fibroblast growth factors]

An acid-soluble protein was isolated from bovine brain tissue using a combination of 5% HClO4 acidic extraction, cation-exchange chromatography and heparin-Sepharose affinity chromatography. This preparation had a biological activity similar to that of the fibroblast growth factor (FGF). It has stimulated neurite outgrowth in organotypic culture of chicken embryo dorsal root ganglia and also has stimulated a proliferation of human embryonic fibroblasts in the culture. The biological activity of isolated preparation was totally inhibited by anti-bFGF antibodies, while anti-aFGF antibodies had no effect. The bFGF showed a neurite stimulating activity in the organotypic culture that was completely abolished by the anti-bFGF, IgG, while the aFGF was inactive. This data, as well as cationic properties of isolated protein and its heparin-binding ability, enable us to postulate a high degree of homology of the brain acid-soluble protein and the bFGF. At the same time the relations of the isolated growth factor and other brain-derived heparin-binding growth factors are yet to be established.     

Fusion of protoplasts in Streptomyces antibioticus

The analysis of Streptomyces antibioticus recombinants isolated under non-selective conditions for stability of inheritance of parental properties demonstrated the existence of non-stable diploids and stable haploid recombinants. Also, genetic analysis of heteroclones isolated on selective medium after plating spores of regenerants was conducted. The results of analysis of haploid recombinant and heteroclones pointed to linkage of genetic loci and the possibility to use the technique of protoplast fusion for establishment of genetic map of S. antibioticus.     

Repair of radiation induced DNA damages in unicellular green algae

Two cell repair systems--photoreactivation and repair of single-strand DNA breaks have been studied using unicellular green algae as a test-system. Effects of the genotype and the intensity of pico/second UV-laser irradiation on the degree of the photoreactivation have been investigated. It has been shown that the lower intensity (I = 8.10(6) W/cm2) effects less the inactivation of living cells comparing with I = 30.10(6) W/cm2, regardless of the genotype. The clearly expressed higher potentials of strains LARG-1 and 260 to produce and repair alterations of the cyclobutane-pyrimidine dimers type have been established. An analysis of DNA degradation during gamma rays irradiation and after incubation has been carried out for investigation the relationship between strains radioresistance and repair of single-strand break. It has been shown that high efficiency of the repair system is characteristic of the resistant strain obtained from chronically irradiated population.